Traveling wave electron discharge device



2 Sheets-Sheet 1 A. W. MGEWAN ETAL TRAVELING WAVE ELECTRON DISCHARGEDEVICE Sept. 17, '1957 Filed Deo. so, 1955 Sept. 17, 1957 A. w. Mol-:WANETAL TRAVEIYING WAVE ELEcTRoN DISCHARGE DEVICE Filed Dec. so, 1955 2Sheets-Sheet 2 xNvEN-roRs A( EKA/VDE@ M NCEWA/V CHARZES AA/OERSO/l BYCAR V. DAM/ELS W C. #de

GENT

United States Patent-Office 2,805,973 Patented Sept. 17, 1957 TRAVELINGWAVE ELECTRGN DISCHARGE DEVICE Alexander W. McEwan, Pompton Lakes,Charles E. A11- derson, Bloomfield, and Carl V. Daniels, Rutherford, N.J., assignors to International Telephone and Telegraph Corporation,Nutley, N. J., a corporation of Maryland Application Becemher 30, 1955,Serial No. 556,507 19 Ciaims. (Cl. S15-3.5)

This invention relates to traveling wave electron discharge devices andmore particularly to radio frequency propagating structures havingalignment members employed to support and align with respect to saidstructures the electron gun of such devices.

The traveling wave type of tube is particularly useful in broadbandmicrowave systems since it is capable of amplifying radio frequencyenergy over an unusually wide band of frequencies. The tube includes aform f slow wave propagating structure, such as a helix or folded stripline, for transmission of microwave energy for interaction with anelectron beam closely associated with the struc-v ture. Thecharacteristic of the propagating structure is such that the velocity ofmicrowave energy conducted along the propagating structure is decreaseduntil it is approximately the same as or slightly lower than thevelocity of the electrons of the beam, whereby the electric field of themicrowave signals interacts with the electron beam for amplification ofthe microwave signals.

The basic components of a traveling wave tube are an envelope, anelectron gun, a collector electrode and a radioV frequency propagatingstructure disposed between the electron gun and collector electrode toprovide the de sii-ed interaction between the radio frequency waves andthe electrons of the electron beam. Heretofore, the various componentshad included their own independent supporting elements, and the inalassembly of the components has been accomplished by employing jigs orsimilar devices for aligning the separate components. Once the alignmenthas been achieved by this process, the components are brazed orotherwise fastened together to provide an aligned arrangement so thatthe electron beam will not be intercepted by components of the tube dueto misalignrnent of these components. As is known, the employment ofjigs for an assembly operation is expensive and time consuming.

lt is an object of this invention to provide a traveling wave electrondischarge device which substantially eliminates the necessity ofemploying alignment jigs or other such devices in the final assembly ofthe components of the traveling wave electron discharge device.

Another object of this invention is to provide a novel construction forpropagating structures of the folded strip line type which cooperates inthe elimination of the alignment jigs of the final assembly of atraveling wave tube.

A feature of this invention is the provision of a slow wave propagatingstructure having a plurality of supporting elements included as anintegral part thereof which are employed to support the electron gun inalignment with the propagating structure and which further cooperates inthe positioning of the electron gun, the collector electrode, andpropagating structure coaxially of the envelope without resorting toalignment jigs.

Another feature of this invention is the provision of a slow wavepropagating structure of the folded strip line type fabricated fromlaminations each having a continuous peripheral conductor dening acentrally disposed opening therethrough. The laminations are dividedinto three different groups. The first of each includes thoselaminations having a conductor projecting in a given direction from oneportion of said peripheral conductor into the central opening thereof,the. second group includes those 'laminations having a conductorprojecting in a direction opposite to said given direction from aportion of said peripheral conductor opposite said one portion into thecentral opening thereof, and a third group includes those laminationshaving conductors projecting from opposite portions of said peripheralconductor into said central opening to a point adjacent a region in thiscentral opening in which the projectingY conductors of the first andsecond groupsV are disposed in overlapping relationship. I helarninations of the lfirst and second groups are alternately disposedwith respect to each other and spaced from each other by laminations o fthe third group. The laminations of each group are disposed in supportedrelationship on a plurality of supporting members. The support membersalign Vthe lamination-sf of the three groups in a manner to provide acircuitous radio wave path longitudinally of the laminatedl propagatingstructure.

' 'The above-mentioned and other features and objects of this inventionwill become more apparent by reference to the following descriptiontaken in conjunction with the accompanying drawings, in which:

v Fig. 1 is a longitudinal cross section of a traveling wave electrondischarge device illustrating the principles of this invention; and

Fig, 2 is an 'exploded view of portions of the propagating structureemployed in the device of Fig. 1.

Referring to Fig. l, the electron discharge `device of this invention isillustrated as comprising an envelope 1 illustrated to be a one-piecemetallic shell, but it it understood that the envelope may be of theusual dielectric type. Envelope 1 includes therein the basic componentswhich are, namely, the electron' gun 2, a collector electrode 3 and aradio frequency propogating structure 4 disposed intermediate theelectron gun 2 and collector electrode 3 in interacting relationshipwith the electron beam projected from gun 2 coaxially of envelope 1. Thepropagating structure 4 is fabricated from a plurality of thinlaminations 5 and alignment rods 6 assembled in a manner to be discussedhereinbelow in connection with Fig. 2 to form a folded strip line typeslow wave structure.

The alignment rods 6 yextend through apertures 7 in magnetic barriermember 8 in a manner whereby plate 9. may be secured to the ends of rods6. The electron gun 2 is fastened by means of at least three ceramicrods 10 to plate 9 substantially as illustrated in Fig. 1 to provide arigid cantilever type electron gun structure which is positionedcoaxially of envelope 1 by the cooperation of magnetic barrier 8 andalignment rod 6. The rearward end of propagating structure 4 issupported by means of the alignment rods 6 extending into apertures inthe magnetic barrier 11 and secured thereto such that the alignment rods6 and magnetic barriers 8 and 11 align propagatingstructure 4, theelectron gun 2 and the collector electrode 3 supported on a magneticbarrier 11. As illustrated in Fig. 1, the magnetic barriers 8 and 11have axially disposed apertures therein to enable the passage of theelectron beam down the properly aligned propagating structure 4 throughmagnetic barrier 11 and, hence, to the collector 3 which includestherein a slanted portion 12 which reduces secondary emission therefromand which is composed of molybdenum or similar metal to absorb thekinetic energy of the electron beam without vaporizing the metal.

Radio frequency energy is introduced by input waveguide 13 at the inputend of propagating structure 4 adjacent electron gun 2. The impedancetransformation fromv waveguidel to the laminated propagating structureis accomplishedby means of a ridge 14 which is electrically secured tothe first lamination of propagatlngrstructure 4 as indicated at 15. Uponcompletion of the interaction between the electron beam and the radiofrequency energy, the radio frequency energy is coupled from thepropagating structure by an extension 16 of the last lamination and anextension'31 of the third lamination 5c from the end of structure 4.Extension 16 is electrically connected to ridge 17, employed as theimpedance transformer between the laminated folded stripline propagatingstructure and the output waveguide 18. Extension 31 is extended to makeelectrical contact with the outer wall of waveguide 18 to complete theimpedance transformation as primarily established by ridge 17.

When the electron discharge device is placed in operation, the device ispositioned in an electromagnet or permanent magnet 19 and is properlypositioned with respect thereto by the external pole piece 20.

Referring now to Fig. 2, the propagating structure 4 will be discussedin greater detail. The propagating structure 4 includes a plurality oflaminations 5 each having a peripheral conductor 21 with alignmentaperturesV 22V therethrough. As illustrated, the peripheral conductor 21may take a rectangular configuration or any other suitable configurationdependent upon the applicanon of the propagating structure. Theperipheral conductor 21 defines a centrally disposed opening 23therethrough. The laminations 5 may be divided into three groups.Y Theiirst group is -composed of those laminations, 'as illustrated bylamination 5d, having a central conductor 24 projecting in a givendirection from one portion of the peripheral conductor 21 into thecentralV opening 23. The second group is composed of those laminations,as illustrated by lamination 5e, including a center conductor 24aprojecting in a direction opposite to thatof conductor 24 from theopposite portion of the peripheral conductor 21 into the central opening23. l`he third group is composed of those laminations, as illustrated bylamination 5f, including conductors 25 and 26 which project fromopposite portions of peripheral conductor 21 into the central opening.It will be noticed that conductors 24 and 24a extend to a point to be inoverlapping relationship'in a region centrally disposed 1n opening 23.This region of overlap will coincide substantially axially with theelectron beam projected down the propagating structure, and as aconsequence, each of the projecting conductors 24 includes therein anaperture 27 enabling the passage of the electron beam through thelaminations of the iirst and second groups. The projecting conductors 25and 26 of lamination 5f extend to a point adjacent the region of overlapof conductors 24 and 24a to the extent that these projections do notobstruct the path of the electron beam.

The length of the region of overlap of conductors 24 and 24a may becontrolled by the conductors 28 and 29 of the laminations in the firstand second groups, respectively. These conductors 28 and 29 extend to apoint spaced from projections 24 and 24a providing a passagetherebetween. In assembling the laminations on support rods 6, thelaminations 5d and 5e of the iirst and second groups, respectively, areplaced alternately on alignment rods 6 spaced from each other by thespacing lamination 5f. The alternation of the laminations of group 1 andgroup 2 spaced from each other by spacers of group 3 provides acircuitous radio wave path longitudinally of propagating structure 4, asindicated by the passage 30 in Fig. l. As pointed out hereinabove, thealignment rods 6 cooperate With magnetic barriers 8 and 11 to supportthe propagating structure 4 coaxially of envelope 1 and further supportelectron gun 2 in alignment with propagating structure 4.

The laminations at the input and output end of propagating structure 4are slightly modiied with respect to the other laminations of thestructure to accept the input and output waveguides i3 and 1S,respectively, and the ridge transformer associated therewith. As will beobserved, the peripheral conductor of the last two laminations areopened on one side thereof for receipt of the waveguide walltherebetween. lt will be further observed that the projecting Vconductoris extended to make contact with the ridge transformers 14 and 17 at theinput and output end of propagating structure 4, respectively. It willbe further observed at the output end of propagating structure 4 thatthe lamination 5c has an extension 31 thereon to cooperate with one edgeof the ridge 17 to provide the desired impedance transformation betweenthe waveguide output line 18 and the folded strip line type-slow wavepropagating structure.

The laminations of groups 1 and 2 are stamped in the same operation toprovide the central projecting conductors, the peripheral conductor andthe holes therethrough for receipt of the alignment rods numbering two,three or four, with satisfactory results being obtained with only twoelements 6. In assembling the laminations on the alignment rods, the topand bottom portions of conductors 21 of the laminations of group 2 arereversed to provide the proper direction for their projecting conductor.Due to possible imperfections in the stamping equipment, the laminationsmay be stamped in the form ofV a parallelogram in which case theopenings 22 of the various groups would not be properly disposed toprovide perfect alignment between the laminations of all the groups.This misalignment may be corrected if the laminations of one group arealsorreversed end for end.

While we have described above the principles of our invention inconnection with specific apparatus, it is to be clearly-understood thatthis description is made only by way of example and notas a limitationto the scope of our invention as 'set forth in the objects thereof andin the accompanying claims.

We claim:

l. In a traveling wave electron discharge device having means forinteraction between an electron beam owing therethrough and a radiofrequency wave traveling therealong, an envelope, an electron gundisposed at one end of said envelope to produce a beam of electrons forprojection along a given path axially of said envelope, a radiofrequency slow wave propagating structure disposed longitudinally ofsaid envelope to enable interaction between a radio frequency wavetraveling therealong and the electrons of said beam, said propagatingstructure including a plurality of alignment members extending asubstantial length of said envelope, and means including said alignmentmembers to longitudinally align said electron gun and said propagatingstructure and to support said electron gun and said propagatingstructure coaxially of said envelope, said means further includes meansin said electron gun for engaging said alignment members to support andcarry said electron gun on said alignment members.

2. A device according to claim l, wherein said proi pagating structureincludes a plurality of laminations'each having a continuous peripheralconductor defining a centrally disposed opening therethrough, a iirstgroup of said laminations including a conductor projecting in a givendirection from one portion of said peripheral conductor into saidcentral opening, a second group of said laminations including aconductor projecting in a direction opposite to said given directionfrom a portion of said peripheral conductor opposite said one portioninto said central opening, the end portions of said projectingconductors of said iirst and second groups each extending into a region'disposed centrally of said central opening, a third group of saidlaminations having conductors projecting from opposite portions of saidperipheral conductor into said central opening to a point adjacent saidregion, the laminations of said iirst and second groups beingalternately disposed with respect to each other and spaced from eachother by laminations of said third group to prolaminations includeapertures therethrough disposed coaxially of said envelope for thepassage of said electron beam. i

4. A device accomhng to claim l, wherein said means including saidalignment members further includes a first annular disk disposedcrosswise said envelope adjacent said electron gun having aperturestherethrough, given ones of the apertures of said rst disk receiving oneend of said alignment members and a second annular disk disposedcrosswise said envelopel adjacent the other end of said envelope havingapertures therethrough, given ones of the apertures of said second diskreceiving the other end of said alignment members.

5. A device according to claim 4, wherein said electron gun includes aplurality of electrodes, a plurality of dielectric rods disposed toextent through the peripheral portion of said electrodes for supportthereof in a predetermined spaced relation and a plate to secure one endof said rods thereto for support and positioning said electrodes, saidplate having apertures therein aligned with the apertures of said tirstdisk, given ones of the apertures of said plate fitting said one end ofsaid alignment member for support or said electron gun and alignmentthereof with respect to said propagating structure.

6. A device according to claim 5, wherein the apertures of said rst andsecond disks and said plate each include an aperture disposed coaxiallyof said envelope for the passage of said electron beam.

7. A traveling wave electron discharge device comprising an envelope, acollector electrode disposed at one end of said envelope, an electrongun disposed at the other end of said electrode to project a beam ofelectrons along a given path between said electron gun and saidcollector electrode axially of said envelope, a radio frequency slowwave propagating structure disposed coaxially of said given path havingalignment members extending substantially the entire length of saidenvelope, a radio frequency input means for coupling radio frequencywaves to one end of said propagating structure for propagationtherealong in interacting relation with the electrons of said beam, aradio frequency output means Vfor coupling radi frequency waves from theother end of said propagating structure, and means including saidalignment members to longitudinally align said electron gun, saidcollector electrode and said propagating structure and to support saidelectron gun, said collector electrode and said propagating structurecoaxially of said envelope, said means further includes means in saidelectron gun and means in said collector electrode for engagingrespective ends of said alignment members to support and carry saidelectron gun and said collector electrode on said alignment members.

8. A device according to claim 7, wherein said electron gun includes aplate having a plurality of apertures therethrough, one of the aperturesthereof being centrally disposed, and means supporting the electrodes ofsaid electron gun from said plate and said means including saidalignment members further includes a rst annular disk disposed crosswisesaid envelope adjacent said electron gun having apertures therethrough,one of the apertures thereof being centrally disposed and others of theapertures thereof enabling the extension of one end of said alignmentmembers therethrough for engagement with certain apertures of said platefor support of said plate and alignment of said one aperture of saidplate with said one aperture of said rst disk and a second annular diskdisposed crosswisey saidv envelope at the other end of said alignmentmembers, and means securing said collector centrally disposed and othersof the apertures thereof,

engaging the other end of said alignment members to supportsaidcollector electrode in alignment with said electron gun and saidpropagating structure.

9. A device accordingy to claim 7, wherein said radio frequency inputmeans and output means each include a radio frequency waveguide coupledto said propagating structure and an impedance transformer of the ridgedtype disposed within said waveguide to match the impedance of saidwaveguide to said propagating structure.

l0. A device according to claim 7, wherein said propagating structureincludes a plurality of laminations each having a continuous peripheralconductor defining a centrally disposed opening therethrough,Z a rstgroup of said laminations including a conductor projecting in a givendirection from one portion of said peripheral conductor into saidcentral opening, a second group of said laminations including aconductor projecting in a direction opposite to said given directionfrom a portion of said peripheral conductor opposite said one portioninto said central opening, the end portions of said projectingconductors of said first and second groups each extending into a regiondisposed centrally of said central opening, a third group of saidlaminations having conductors projecting from opposite portions of saidperipheral conductor into said central opening to a point adjacent saidregion, the laminations of said rst and second groups being alternatelydisposed with respect to each other and spaced from each other bylaminations of said third group to provide a circuitous radio wave pathlongitudinally of the central opening of said laminations, a pluralityof openings disposed in the peripheral conductor of each of saidlaminations for receipt of said alignment members for alignment andsupport of said laminations, andv the projecting conductors of saidfirst and second groups of said laminations include aperturestherethrough disposed coaxially of said envelope for the passage of saidelectron beam.

1l. A travelling wave electron discharge device comprising an envelope,a collector electrode disposed at one end of said envelope, an electrongun disposed at the other end of said electrode to project a beam ofelectrons along a given path between said electron gun and saidcollector electrode axially of said envelope, a radio frequency slowwave propagating structure disposed coaxially of said given path havingalignment members extending substantially the entire length of saidenvelope, a radio frequency input means for coupling radio frequencywaves to one end of said propagating structure for propagationtherealong in interacting relation with the electrons of said beam, aradio frequency output means for coupling radio frequency waves from theother end of said propagating structure, and means including saidalignment members to longitudinally align said electron gun, saidcollector electrode and said propagating structure and to support saidelectron gun, said collector electrode and said propagating structurecoaxially of said envelope, said propagating structure including aplurality of laminations each having a continuous peripheral conductordening a centrally disposed opening therethrough, a tirst group of saidlaminations including a conductor projecting in a given direction fromone portion of said peripheral conductor into said central opening, asecond group of said laminations including a conductor project-- ing ina direction opposite to said given direction from a portion of saidperipheral conductor opposite said one portion into said centralopening, the end portions of said projecting conductors of said firstand second groups each extending into a region disposed centrally ofsaid central opening, a third group of Asaid laminations havingconductors projecting from opposite portions of said peripheralconductor into said central opening to a point adjacent said region, thelaminations of said rst and andere l l 'i' Y l second groups beingalternately disposed with respect to each other and spaced from eachother by laminations of said third group to provide a circuitous radiowave path longitudinally of the central opening of said laminations, aplurality of openings disposed in the peripheral conductor of each ofsaid laminations for receipt of Said alignment` members for alignmentand support of said laminations, and the projecting conductors of saidfirst and second groups of said laminations include aperturestherethrough disposed coaxially of said envelope for the passage of saidelectron beam, wherein said radio frequency input means including aradio frequency waveguide, a ridge disposed in said waveguide adjacentthe end thereof, a lamination having an axiallyV disposed apertureincluding an extended portion to make electrical contact with saidridge, and a lamination of said third group having a portion of theperipheral conductor thereof removed to provide radio frequencycommunication between -said 'waveguide and said circuitous path, saidridge matching the impedance of said waveguide to the impedance of saidcircuitous path. Y

l2, AV traveling wave electron discharge device comprising an envelope,a collector electrode disposed at one end of said envelope, an electrongun disposed at the other end of said electrode to project a beam ofelectrons along a given path between said electron gun and saidcollector electrode axially of said envelope, a radio frequency slowwave propagating structure disposed coaxially of said given path havingalignment members extending substantially the entire length of saidenvelope, a radio frequency input means for coupling radio frequencywaves to one end of rsaid propagating structure for propagationtherealong in interacting relation with the electrons of said beam, aradio frequency output means for coupling radio frequency waves from theother end of said propagating structure, and means including saidalignment members to longitudinally align said electron gun, saidcollector electrode and said propagating structure and to support saidelectron gun, said collector electrode and said propagating structurecoaxially of said envelope, said propagating structure including aplurality ofrlaminations each having a continuous peripheral conductordefining a centrally disposed opening therethrough, a first group ofsaid laminations including a conductor projecting in a given directionfrom one portion l of said peripheral conductor into said centralopening, a second group of said laminations including a conductorprojecting in a direction opposite to said given direction from aportion of said peripheral conductor opposite said one portion into saidcentral opening, the end portions of said projecting conductors ofsaidrfirst and second groups each extending into a region disposedcentrally of said central opening, a third group of said laminationshaving conductors projecting from opposite portions of said peripheralconductor into said central opening to a point adjacent said region, thelaminations of said first and second groups being alternately disposedwith respect to each other and spaced from each other by laminations ofsaid third group to provide a circuitous radio wave path longitudinallyof the central opening of said laminations, a plurality of openingsdisposed in the peripheral conductor of each of said laminations forreceipt of said alignment members for alignment and Vsupport of saidlaminations, and the projecting conductors of said first and secondgroups of said laminations include apertures therethrough disposedcoaxially of'said envelope for the passage of said electron beam, saidradio frequency output means including a radioV frequencywaveguide, a`ridge disposed in said waveguide adjacent the end thereof, a laminationVhaving an axially disposed aperture including an extended portion tomake electrical` contact with said ridge, a lamination of one of saidrstand second groups including an extended portion to make contact with awall of said waveguide, and a lamination of said third group having aportion of the peripheral conductor thereof recuitous path and l Y 8 Ymoved to provide radio frequency communication between said waveguideand said circuitous path, said ridge matching the impedance of saidwaveguide to the impedance of said circuitous path.

13. A traveling wave electron discharge device comprising an envelope, acollector electrode disposed at one .Y

end of said envelope, an electron gun disposed at the other end of saidelectrode to project a beam of electrons along a given path between saidelectron gun and said collector electrode axially of said envelope, aradio frequency slow wave propagating structure disposed coaxially ofsaid given path having alignment members extending substantially theentire length of said envelope, a radio frequency input means forcoupling radio frequency waves to one end of said propagating structurefor propagation therealong in interacting relation with the electrons ofsaid beam, a radio frequency output means for coupling radio frequencyWaves from the other end of said propagating structure, and meansincluding said alignment members to longitudinally align said electrongun, said collector electrode and said propagating structure and tosupport said electron gun, said collector electrode and said propagatingstructure coaxially of said envelope, said propagating structureincluding a plurality of laminations each having a continuous peripheralconductor defining a centrally disposed opening therethrough, a firstgroup of said laminations including a conductor projecting in a givendirection from one portion of said peripheral conductor into saidcentral opening, a second group of said laminations including aconductor projecting in a direction opposite to said given directionfrom a portion of said peripheral conductor opposite said one portioninto said central opening, the end portions of said projectingconductors of said iirst and second groups each extending into a regiondisposed centrally of said central opening, a third group of saidlaminations having conductors projecting from opposite portions of saidperipheral conductor into said central opening to a point adjacent saidregion, the laminations of said first and second groups beingalternately disposed with respect to each other andv spaced from eachother by laminations of said third group to provide a circuitous radiowave path longitudinally of the central opening of said laminations, aplurality of openings disposed in the peripheral conductor of each ofsaid laminations for receipt of said alignment members for alignment andsupport of said laminations, and the projectingtconductors of said firstand second groups of said laminations include apertures therethroughdisposed coaxially of said envelope for the passage of said electronbeam, said radio frequency input means including a radio frequencywaveguide extending from a point adjacent said collector electrode to apoint adjacent said electron gun having one wall thereof in electricalcontact with the peripheral conductor of said laminations, a ridgedisposed in said waveguide adjacent the end thereof to be coupled tosaid circuitous path extending from a point spaced from said one wall toa point in contact With the other wall of said waveguide, a laminationhaving an axially disposed aperture including an extended portion tomake electrical Contact with the end of said ridge spaced from said onewall, and a lamination of said third group having a portion of theperipheral conductor removed therefrom adjacent said one wall toVprovide radio frequency communication between said waveguide and saidcirsaid radio frequency output means including a second waveguideextending to a point adjacent said collector electrode, a ridge disposedin said waveguidetadjacent the end thereof to be coupled to saidcircuitous path extending from a point spaced from one wall ofsaid'second waveguide to a point in contact with the other wall of saidsecond waveguide, a lamination of one of said first and second groupsincluding an extended portion to make contact with said one wall of saidsecond waveguide, and a lamination of said third group having r aportion of the peripheral conductor removed therefrom adjacent saidother Wall of said second waveguide to provide `radio frequencycommunication between said waveguide and said circuitous path, saidridges matching the impedance of said waveguides to the impedance ofsaid circuitous path.

14. An energy wave retardation structure .comprising a plurality oflaminations each having a continuous peripheral conductor defining acentrally disposed opening therethrough, ya tirst group off saidlaminations including a conductor projecting in a givenA direction fromone portion of said peripheral conductor into said central opening, asecond group of said laminations including a conductor projecting in a.direction opposite to said given direction from a portion of saidperipheral conductor oppositeV said one portion into said centralopening, the end portions of said projecting conductors of said iirstand second groups. each extending into a region disposed centrally ofsaid central opening,Y a third group of said laminations havingconductors projecting from opposite portions of said peripheralconductor into said central opening to a point adjacent said region, thelaminations of said first and second groups being alternately disposedwith respect to each other and spaced from each other by laminations ofsaid third group to provide a circuitous energy wave path longitudinallyof the central opening of said laminations, and a plurality of membersextending through openings in the peripheral conductor of saidlaminations for alignment and support thereof.

l5. An energy wave retardation, structure comprising a plurality oflaminations each having a continuous peripheral conductor defining acentrally disposed opening therethrough, a first group of said.laminations including a conductor projecting in a given direction fromone portion of said peripheral conductor into said central opening, asecond group of said laminations including a :conductor projecting in adirection opposite to sai-d given direction from a portion of saidperipheral conductor opposite said one portion into said centralopening, the end portions of said projecting conductors of said firstand second groups each extending into a region disposed centrally ofsaid central opening, a third group of said laminations havingconductors projecting from opposite portions of said peripheralconductor into said central opening to a point adjacent said region, thelaminations of said iirst and second groups being alternately disposedwith respect to each other and spaced from each other by laminations ofsaid third group to provide a circuitous energy wave path longitudinallyof the central opening of said laminations and a plurality of membersextending through openings in the peripheral conductor of saidlaminations for alignment and support thereof, input means to coupleenergy into said circuitous path and output means to couple energy outof said circuitous path. A

16. An energy wave retardation structure comprising a plurality oflaminations each having a continuous peripheral conductor dening acentrally disposed opening therethrough, a iirst group of saidlaminations iucluding a conductor projecting in a given direction fromone portion of said peripheral conductor into said central opening, asecond group of said laminations including a conductor projecting in adirection opposite to said given direction from a portion of saidperipheral conductor opposite said one portion into said centralopening, the end portions of said projecting conductors of said firstand second groups each extending into a region disposed centrally ofsaid central opening, a third group of said laminations havingconductors projecting from opposite portions of said peripheralconductor into said central opening to a point adjacent said region, thelaminations of said iirst and second groups being alternately disposedwith respect to each other and spaced from each other by laminations ofsaid third group to provide a circuitous energy wave path longitudinallyof the central vide for communication between said waveguide and said,

circuitous path, said ridge matching the impedance of said waveguide tothey impedanceV of said circuitous path.

i7. An energy wave retardation structure comprising a plurality oflaminations each having a continuous peripheral conductor defining acentrally disposed opening there through, a first group of saidvlaminations including a conductor projecting in a givendirection fromone portion of said peripheral conductor into said central opening, asecond group of said laminations including a conductor projecting in adirection opposite, to said given direction from a portion ofsaidpelipheral conductor opposite said one portion into said centralopening, the end portions of said projecting conductors of said firstand second groups each extending into a region disposed centrally ofsaid central opening, a third group. of said laminations havingconductors projecting from opposite portions of said peripheralconductor into said central opening to a point adjacent said region, thelaminations of said first and second groups being alternately disposedwith; respect to, each other and spaced from each other by laminationsof said third group to provide a circuitous energy wave pathlongitudinally of the central opening of said laminations and aplurality of members extending through openings in the peripheralconductor of said laminations for alignment and support thereof, inputmeans to couple energy into said circuitous path rand output means tocouple energy out of said circuitous path, said output means including awaveguide, a ridge disposed in said waveguide adjacent the end thereof,a lamination having an axially disposed aperture including an extendedportion to make electrical contact with said ridge, a lamination of oneof said first and second groups including an extended portion to makecontact with a wall of said waveguide, and a lamination of said thirdgroup having a portion of the peripheral conductor thereof removed toprovide for communication between said waveguide and said circuitouspath, said ridge matching the impedance of said waveguide to theimpedance of said circuitous path.

18. An energy wave retardation structure comprising a plurality ofrectangular laminations each having a continuous peripheral rectangularconductor defining a centrally disposed rectangular opening therethroughand an aperture adjacent each corner of said peripheral conductor, afirst group of said laminations including a conductor projecting in agiven direction from one portion of said peripheral conductor into saidcentral opening, a second group of said laminations including aconductor projecting in a direction opposite to said given directionfrom a portion of said peripheral conductor opposite said one portioninto said central opening, the end portions of said projectingconductors of said first and second groups each extending into a regiondisposed centrally of said central opening, a third group of saidlaminations having conductors projecting from opposite portions of saidperipheral conductor into said central opening to a point adjacent saidregion, the laminations of said first and second group being alternatelydisposed with respect to each other and spaced from each other bylaminations of said third group to provide a circuitous energy wave pathlongitudinally of the central opening of said laminations, a pluralityof members extending through certain of the apertures of the peripheralconductor of said laminations for alignment [and support thereof, inputmeans to couple energy into said circuitouspath, and output means tocouple energy out of said circuitous path. Y

19` An energy wave retardation structure comprising a plurality ofrectangular laminations eachV having a continuous peripheral rectangularconductor defining a ccntrally disposed rectangular opening therethroughand an aperture adjacent each corner of said peripheral conductor, a rstgroup of said laminations including a conductor into said centralopening, a second group of said laminations including a conductorprojecting in a direction opposite to said given direction from aportion of said peripheral conductor opposite said one portion into saidcentral opening, the end portions of said projecting conductors of saidrst and second groups each extending into a region disposed centrally osaid central opening, a third group of said laminations havingconductors projecting from opposite portions of said peripheralconductor into said central opening to a point adjacent said region, thelaminations of said first and second groups being alternately disposedwith respect to each other and spaced from each other by laminations ofsaid third group to provide a circuitous energy wave path longitudinallyof the central opening of said laminations, a plurality of membersextending through certain of the apertures of the peripheral conductorol" said laminations for alignmentand support thereof, input means tocouple energy into said circuitous path, and output means to coupleenergy out of said circuitous path, said input means including awaveguide extending from a point adjacent said collector electrode to apoint adjacent said electron gun having one wall thereof in electricalcontact with the peripheral conductor of said laminations, a ridgedisposed in said waveguide adjacent the end thereof to be coupled tosaid circuitous path extending from 12 a point spaced from said one wallto a point in contact with the other wall of said waveguide, alamination having an axially Idisposed aperture including an extendedportion to make electrical Contact with the end of said ridge spacedfrom said one wall, and a lamination of said third group having aportion of the peripheral conductor removed therefrom adjacent said onewall to provide forcommunication between said waveguide and saidcircuitous path and said radio frequency output means including a secondwaveguide extending to a point adjacent said collector electrode, aridge disposed in said waveguide adjacent the end thereof to be coupledto said circuitous path extending from a point spaced from one wall ofsaid second waveguide to a point in contact with the other wall of saidsecond waveguide, a lamination of one of said first and second groupsincluding an extended portion to make contact with said one wall of saidsecond waveguide, and a lamination of said third group having a portionof the peripheral conductor removed therefrom adjacent said other wallof said second waveguide to provide for communication between saidwaveguide and said circuitous path, said ridges matching the impedanceof said waveguides to the impedance of said circuitous path.

References Cited in the file of this patent VUNITED STATES PATENTS2,444,080 Williams June 29, 1948 2,463,416 Nordsieck Mar. l, 19492,477,122 Garner July 26, 1949 2,662,148 Pierce July 1, 1952 2,653,270Kompfner Sept. 22, 1953 2,692,351 Morton Oct. 19, 1954

